Perforated sheet material



April 28, 1970 F. KALWAITES PERFORATED SHEET MATERIAL Original Filed March 5, .1965

Rs Y E WWLM EA 0 vw %m WL K M 5M United States Patent 3,509,007 PERFORATED SHEET MATERIAL Frank Kalwaites, Somerville, N.J., assignor to Johnson & Johnson, a corporation of New Jersey Original application Mar. 5, 1965, Ser. No. 437,469, now Patent No. 3,408,776, dated Nov. 5, 1968. Divided and this application Mar. 18, 1968, Ser. No. 713,690 Int. Cl. B32b 3/10 US. Cl. 161110 3 Claims ABSTRACT OF THE DISCLOSURE Perforated sheet material having a smooth face and a roughened face. Portions of the material about each perforation extend out of the plane of the material and are set in such a configuration.

Thi is a divisional application of my co-pending application Ser. No. 437,469, filed Mar. 5, 1965, now US. Patent 3,408,776, issued Nov. 5, 1968.

This invention relates to apparatus for producing perforated sheet material, and more particularly to perforated sheet material in which the perforations are formed by a combination of abrading and shredding of minute areas of the sheet material to form apertures in the same.

There are various known techniques for producing perforated sheet material, such as by completely cutting out areas and removing these areas to form the perforations or by partially cutting portions and bending these partially cut portions back to form a flap and an adjoining perforation. Furthermore, there are techniques, when thermoplastic materials are used, of heating small areas of the sheet material to form perforations. All of these prior art perforated sheet materials have their various advantages and disadvantages. For example, those where only a portion of the area is cut and bent back to form a flap have the advantage that when used in combination with a loose batt of short fibers or wood pulp, the flap tends to stabilize the batt; however, these flaps very often fold back and close up the hole, and hence, reduce the desired permeability of the sheet material. If the area is completely removed to form a clean hole, two smooth surfaces are formed on the perforated sheet material, and the advantage of stabilizing the materials laminated with the perforated sheet material is lost, but the advantage of uniform consistent permeability is gained.

The perforated sheet material of the present invention is two-faced, that is, it has one face with portions of material extending from the surface so that this surface can be applied against a loose batt of fibers to stabilize the fibers. Furthermore, these portions are not full flaps and have no tendency to reclose the apertures and hence, the perforated sheet materials of the present invention have uniform consistent permeability. The opposite face of the perforated sheet material of the present invention is smooth and may be applied against areas in which smoothness and softness are desired.

My new apertured sheet material may be produced with uniformly spaced and uniformly sized apertures. The apertures may vary in size from very minute to quite large. The perforated sheet material may be produced at great speeds with simple equipment. In my heet material there is no fiap which tends to fall back and cover the aperture, thus preventing desired porosity. The new apertured sheet material of the present invention has one face which is smooth while the opposite face is roughened. On the roughened face a portion of the material initially in the aperture surrounds a portion of the periphery of the aperture. This material stick out of the plane of the sheet material and is torn and shredded and is set in its configuration out of the plane of sheet mate- 'ice rial. This fiap portion has substantially no tendency to close the aperture, and in those instances where it is forced back into the aperture, it only closes a portion of the aperture.

The apertured sheet material of the present invention is made by supporting the material to be perforated at spaced areas over one surface allowing material to deflect or drape out of the general plane of the material between the supported spaced areas, and abrading the opposite surface at these spaced supported areas to scuff, disrupt, and tear the heet material in these spaced areas. A portion of the material in these areas is removed while the remainder is bent back about a portion of the periphery of the area. This bent back portion is set in its bent condition by the scuffing or tearing action, and in those instances where a thermoplastic sheet material is used, the heat produced by the scufiing or friction action tends to set the thermoplastic material into its bent back configuration to form uniformly sized perforations in the sheet material.

The invention will be more fully described when taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a plan view of the apertured sheet material of the present invention;

FIGURE 2 is an enlarged cross-sectional view of a portion of the sheet material shown in FIGURE 1 taken along line 22..

FIGURE 3 is a perspective view of one form of apparatus for practicing the present invention.

Referring to the drawings, in FIGURE 1 there is depicted an apertured sheet marterial 14 of the present invention. Areas of the sheet material have been torn, scuffed and shredded to produce apertures 15. Portions 16 of the material, previously in the apertures, now surround a portion of the periphery of each aperture. As more clearly shown in FIGURE 2 this material 16 is out of the general plane of the sheet material in more or less the form of a flap. The flap is not large enough to fill the aperture as a portion of the material has been abraded away.

Examples of various sheet materials which may be performed in accordance with the present invention are paper, thermoplastic film, vinyl films, etc. The perforations may have a variety of shapes, such as round, elliptical, square, polygonal, or combinations thereof. Size and spacing of the perforations may also be varied.

Apparatus for perforating the sheet material in accordance with the present invention is depicted in FIGURE 3. The material 25 to be perforated is fed onto the surface of a rotating roll 26. The roll is covered with a number of raised projections 27, the ends of these projections having flat surfaces 28. The number of projections will depend upon the distribution of perforations desired in the final product. It is essential that there be sufficient fiat area on these projections to support the filrn, and the sheet material not penetrated by these projections. Furthermore, the projections have a depth greater than the thickness of the sheet material being processed. Approximately 20,000 projetcions per square foot each having a flat area of 0.0007 square inch have been found suitable. However, projections ranging in number from about per square foot to 150,000 per square foot having areas in the range of from about 0.0001 square inch to about 0.1 square inch also have been found suitable. Spacing of perforations will depend to a large extent on the flexibility of the sheet material being processed. The projections must be spaced far enough apart to allow the sheet material to drape down between the projections. In operation the film passes underneath roll 30 and is stretched about by tension on the surface of the raised projections. The film then passes through the nip formed by roll 31. The roll 31 is covered with an abrading surface 32, which as depicted in FIGURE 3 is an emery cloth type surface. The abrading roll operates at surface linear speeds from about two to fifty or more times as fast as the roll having the raised projections. The abrading roll scuffs, tears, and abrades away a substantial portion of the sheet material in contact with the flat surfaces of the raised projection. That material which is not abraded away is bent back about a portion of the periphery of the perforation formed and on passing through the tight nip is set in its bent back position so that uniform perforations are produced.

The sheet material actually is allowed to sag between the raised projections so that when abraded by the abrading roll only the portions of the film in contact with the outermost area of each projection is abraded away. The differential in speeds between the raised projection roll and the abrading roll will depend to a great extent on the sheet material being processed and the clarity desired in the perforations.

In perforating sheet materials in accordance with the present invention, that portion of the material which is removed from the hole and is still left attached to the base sheet material is pressed or set in a bent back condition as it passes through the nip formed by the two rolls, and hence, during subsequent use it will not tend to reenter the area of the perforation and close the perforation. Furthermore, if thermoplastic materials are being perforated, the friction accompanying the abrading action heat sets the bent back portion in its bent condition and substantially prevents it from returning to close the perforation.

The invention will be further illustrated in greater detail by the following specific examples. It should be understood, however, that although these examples may describe in particular detail some of the more specific features of the invention, they are given primarily for purposes of illustration, and the invention in its broader aspects is not to be construed as limited thereto.

In the drawings no driving means, such as motors, pulleys, belts, gears, sprockets, and the like have been illustrated for either roll. It must be understood that this has been done because such driving means are conventional and well known in the art. Furthermore, no frame or support means are shown and again, this is done because such are conventional and well known in the art. Additionally, the omission of these parts from the drawings makes the individual figures thereof less complicated and easier to read and to understand.

EXAMPLE I A one mil polyethylene film is taken'from a let-off roll and passed under an idler roll so as to wrap around and contact a pattern roll. The pattern roll is 8 inches in diameter and is covered with fillet wire clothing No. 4R3R11N 1 /2 inches wide. The wire is No. 21 wire having approximately 160 points per square inch. Cooperating Cooperating with this pattern roll is an abrading roll. The abrading roll is positioned to form a nip, and the abrading roll is covered with One hundredth fillet Wire and having about 72,000 points per square foot. The wire is No. 32 and has a diameter of approximately .0128 inch. The rolls rotate in opposite directions and the abrading roll rotates at approximately 20 times the surface linear speed of the pattern roll. The film, after passing in contact with a portion of the surface of the pattern roll so that the film deflects between the wires, is passed between the nip formed by the abrading roll, and portions of the film corresponding to the points on the pattern roll are abraded away, scuffed and bent back. In the final film, the perforations are on approximately inch centers. There are approximately 138 perforations per square inch.

On one surface of the film about the periphery of each perforation, there is a small fiap of scuffed up film. If this flap is pressed back into the area from which it was removed, and then released, it immediately folds back and opens the perforation. It appears that the friction evolved during the abrading action has partially set this fiap in an open condition.

EXAMPLE II The procedure of Example I is followed as set forth therein with the exception that creped tissue paper having a 13 pound basis weight is substituted for the polyethylene film. The paper is perforated in the manner as described in conjunction with Example I and paper having approximately 138 perforations per square inch is produced. The perforations are uniformly spaced and uniform in side, and the portion of the paper surrounding the periphery of each perforation stays in its bent back condition and does not close perforations.

EXAMPLE III The procedure as outlined in Example I is followed as set forth therein with the exception that an abrading roll covered with a medium grade emery cloth is substituted for the fine toothed abrading roll of Example I. The abrading roll is set to just kiss the points of the pattern roll. Comparable results to those obtained in Example I are obtained in this example.

It should be further understood that the above examples are for the purposes of illustration only and are not to be used to delineate the breadth or scope of the invention. The invention is only limited by the scope of the claims appended hereto.

I claim:

1. A flexible perforated sheet material having one smooth face and the opposite face slightly roughened, the perforations being substantially uniformly spaced and being substantially uniform in size, portions of material about a section of the periphery of each perforation extending out of the general plane of the material whereby said material portions are available for stabilizing loose fibrous batts when said portions are in contact with said fibrous batts, the free edge of each material portion being irregular and having an abraded appearance, said material portions being insufficient to cover the adjacent perforation whereby said sheet material has uniform permeability, said portions being set in their configuration out of the plane of the sheet material, said material portions all being disposed in the same direction and being attached to similar sections of the periphery of each perforation.

2. Material according to claim 1 wherein the perforated sheet material is perforated paper.

3. Material according to claim 1 wherein the perforated sheet material is a perforated thermoplastic film and the portions out of the plane of the material are heat-set.

References Cited UNITED STATES PATENTS 24,968 8/1859 Warburton 264-156 1,167,603 1/1916 Swift 161-110 3,292,619 12/1966 Egler 161113 XR 3,307,545 3/1967 Surowitz 161-109 XR J. STEINBERG, Primary Examiner.

R. H. CRISS, Assistant Examiner U.S. Cl. X.R. 1611 11 Patent No. 3,509,007 April 28, 1970 Frank Kalwaites It is certified the patent and that said Let shown below:

t error appears in the above identified hers Patent are hereby corrected as Column 1, line 16, after "configuration. insert The extended portions are of a size which is insufficient to cover the adjacent perforation. These portions are available for stabilizing loose fibrous b atts when in contact with such batts.

Signed and sealed this 15th day of December 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr.

WILLIAM E. SCHUYLER, JR. Attesting Officer I Commissioner of Patents 

